Question 139291
In one week she earned $390 for working 47 hours of which 7 hours were overtime. The next week she earn $416 for working 50 hours of which 8 hours were obertime. What is Sally's hourly overtime rate in dollars per hour? 
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Let overtime rate = x; Let regular rate = y:

EQUATIONS:
7x + 40y = 390
8x + 42y = 416
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Multiply 1st equation by 8 and 2nd equation by 7 to get:
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56x + 320y = 8*390
56x + 294y = 7*416
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Subtract 2nd from 1st to get:
26y = 3120-2912
26y = 208
y = $8.00 (regular hourly rate)
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Substitute that into original 1st eq. to get:
7x + 40*8 = 390
7x = 70
x = $10.00 (overtime rate)
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Cheers,
Stan H.